Experimental studies on a high performance thermoelectric system based on micro opposed flow porous combustor

Monitoring and detecting carbon monoxide (CO) are critical because this gas is toxic and harmful to the ecosystem. In this respect, designing high-performance gas sensors for CO detection is necessary. Zinc oxide-based materials are promising for use as CO sensors, owing to their good sensing response, electrical performance, cost-effectiveness, long-term stability, low power consumption, ease of manufacturing, chemical stability, and non-toxicity. Nevertheless, further progress in gas sensing requires improving the selectivity and sensitivity, and lowering the operating temperature. Recently, different strategies have been implemented to improve the sensitivity and selectivity of ZnO to CO, highlighting the doping of ZnO. Many studies concluded that doped ZnO demonstrates better sensing properties than those of undoped ZnO in detecting CO. Therefore, in this review, we analyze and discuss, in detail, the recent advances in doped ZnO for CO sensing applications. First, experimental studies on ZnO doped with transition metals, boron group elements, and alkaline earth metals as CO sensors are comprehensively reviewed. We then focused on analyzing theoretical and combined experimental–theoretical studies. Finally, we present the conclusions and some perspectives for future investigations in the context of advancements in CO sensing using doped ZnO, which include room-temperature gas sensing.

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Computational Molecular Modeling of Transport Processes in Nanoporous Membranes

Processes ◽

10.3390/pr6080124 ◽

2018 ◽

Vol 6 (8) ◽

pp. 124 ◽

Cited By ~ 10

Author(s):

Kevin Hinkle ◽

Xiaoyu Wang ◽

Xuehong Gu ◽

Cynthia Jameson ◽

Sohail Murad

Keyword(s):

Molecular Modeling ◽

Temporal Resolution ◽

High Performance ◽

Low Cost ◽

Membrane Surface ◽

Experimental Studies ◽

Nanoporous Materials ◽

Transport Processes ◽

Zeolite Membrane ◽

Nanoporous Membranes

In this report we have discussed the important role of molecular modeling, especially the use of the molecular dynamics method, in investigating transport processes in nanoporous materials such as membranes. With the availability of high performance computers, molecular modeling can now be used to study rather complex systems at a fraction of the cost or time requirements of experimental studies. Molecular modeling techniques have the advantage of being able to access spatial and temporal resolution which are difficult to reach in experimental studies. For example, sub-Angstrom level spatial resolution is very accessible as is sub-femtosecond temporal resolution. Due to these advantages, simulation can play two important roles: Firstly because of the increased spatial and temporal resolution, it can help understand phenomena not well understood. As an example, we discuss the study of reverse osmosis processes. Before simulations were used it was thought the separation of water from salt was purely a coulombic phenomenon. However, by applying molecular simulation techniques, it was clearly demonstrated that the solvation of ions made the separation in effect a steric separation and it was the flux which was strongly affected by the coulombic interactions between water and the membrane surface. Additionally, because of their relatively low cost and quick turnaround (by using multiple processor systems now increasingly available) simulations can be a useful screening tool to identify membranes for a potential application. To this end, we have described our studies in determining the most suitable zeolite membrane for redox flow battery applications. As computing facilities become more widely available and new computational methods are developed, we believe molecular modeling will become a key tool in the study of transport processes in nanoporous materials.

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An analytical model for predicting the shear strength of unsaturated soils

Proceedings of the Institution of Civil Engineers - Geotechnical Engineering ◽

10.1680/jgeen.21.00135 ◽

2022 ◽

pp. 1-57

Author(s):

Tuan A. Pham ◽

Melis Sutman

Keyword(s):

Shear Strength ◽

Analytical Model ◽

Unsaturated Soils ◽

High Performance ◽

Micromechanical Model ◽

Experimental Studies ◽

Stress Equilibrium ◽

Proposed Model ◽

New Equation ◽

Multi Phase

The prediction of shear strength for unsaturated soils remains to be a significant challenge due to their complex multi-phase nature. In this paper, a review of prior experimental studies is firstly carried out to present important pieces of evidence, limitations, and some design considerations. Next, an overview of the existing shear strength equations is summarized with a brief discussion. Then, a micromechanical model with stress equilibrium conditions and multi-phase interaction considerations is presented to provide a new equation for predicting the shear strength of unsaturated soils. The validity of the proposed model is examined for several published shear strength data of different soil types. It is observed that the shear strength predicted by the analytical model is in good agreement with the experimental data, and get high performance compared to the existing models. The evaluation of the outcomes with two criteria, using average relative error and the normalized sum of squared error, proved the effectiveness and validity of the proposed equation. Using the proposed equation, the nonlinear relationship between shear strength, saturation degree, volumetric water content, and matric suction are observed.

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Design, fabrication and experimental studies of compliant flexure diaphragm for micro pump

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i2.21.11838 ◽

2018 ◽

Vol 7 (2.21) ◽

pp. 66 ◽

Cited By ~ 1

Author(s):

R Roopa ◽

P Navin Karanth ◽

S M. Kulkarni

Keyword(s):

Polyvinylidene Fluoride ◽

High Performance ◽

Experimental Studies ◽

Single Layer ◽

Operating Voltage ◽

Driving Voltage ◽

Element Analysis ◽

Central Deflection ◽

Large Numbers ◽

Micro Pump

This study reports the performance of piezo actuated compliant flexure diaphragm for micropump and MEMS application. To achieve the high performance of diaphragm at the low operating voltage compliant flexure diaphragm design is introduced. Very limited work has done on the diaphragms of micropump. Large numbers of mechanical micropumps have used plane diaphragms. The central deflection of diaphragm plays an important role in defining the micropump performance. The flow rate of mechanical type micropump strongly depends on the central deflection of diaphragm. In this paper compliant flexure diaphragms are designed for micropump to achieve higher deflection at lower operating voltage. Finite element analysis of compliant flexure diaphragm with single layer PVDF (Polyvinylidene fluoride) actuator is simulated in COMSOL. Compliant flexure diaphragms with a different number of flexures are analyzed. The central deflection of compliant flexure diaphragms is measured for driving voltages of 90V to 140V in 10 steps. The deflection of the compliant flexure diaphragm mainly depends on flexure width and length, the number of flexures in the diaphragm, PVDF thickness, diaphragm thickness and driving voltage. Use of compliant flexure diaphragm for micropump will reduce the mass and driving voltage of micropump. An attempt is made to compare the results of compliant flexure diaphragms with plane diaphragms. From the experimental results it is noticed that the compliant flexure diaphragm deflection is twice that of the plane diaphragm at same driving voltage. Deflection of three flexure and four flexure compliant diaphragms is 10.5µm and 11.5µm respectively at 140V.

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Experimental studies of analog signal digital representing based on a high performance Event Timer

2014 14th Biennial Baltic Electronic Conference (BEC) ◽

10.1109/bec.2014.7320583 ◽

2014 ◽

Cited By ~ 1

Author(s):

Armands Mezerins

Keyword(s):

High Performance ◽

Experimental Studies ◽

Analog Signal ◽

Event Timer

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Platinum–copper single atom alloy catalysts with high performance towards glycerol hydrogenolysis

Nature Communications ◽

10.1038/s41467-019-13685-2 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 33

Author(s):

Xi Zhang ◽

Guoqing Cui ◽

Haisong Feng ◽

Lifang Chen ◽

Hui Wang ◽

...

Keyword(s):

Active Sites ◽

High Performance ◽

Reaction Pathway ◽

Theoretical Calculations ◽

Experimental Studies ◽

Value Added ◽

Catalytic Performance ◽

Single Atom ◽

Glycerol Hydrogenolysis ◽

Single Atom Alloy

AbstractSelective hydrogenolysis of biomass-derived glycerol to propanediol is an important reaction to produce high value-added chemicals but remains a big challenge. Herein we report a PtCu single atom alloy (SAA) catalyst with single Pt atom dispersed on Cu nanoclusters, which exhibits dramatically boosted catalytic performance (yield: 98.8%) towards glycerol hydrogenolysis to 1,2-propanediol. Remarkably, the turnover frequency reaches up to 2.6 × 103 molglycerol·molPtCu–SAA−1·h−1, which is to our knowledge the largest value among reported heterogeneous metal catalysts. Both in situ experimental studies and theoretical calculations verify interface sites of PtCu–SAA serve as intrinsic active sites, in which the single Pt atom facilitates the breakage of central C–H bond whilst the terminal C–O bond undergoes dissociation adsorption on adjacent Cu atom. This interfacial synergistic catalysis based on PtCu–SAA changes the reaction pathway with a decreased activation energy, which can be extended to other noble metal alloy systems.

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Evaluation of Various Scintillator Materials in Radiation Detector Design for Positron Emission Tomography (PET)

Crystals ◽

10.3390/cryst10100869 ◽

2020 ◽

Vol 10 (10) ◽

pp. 869

Author(s):

Siwei Xie ◽

Xi Zhang ◽

Yibin Zhang ◽

Gaoyang Ying ◽

Qiu Huang ◽

...

Keyword(s):

Positron Emission Tomography ◽

High Performance ◽

Radiation Detector ◽

Experimental Studies ◽

Light Output ◽

Radiation Detectors ◽

Emission Tomography ◽

Timing Resolution ◽

Positron Emission ◽

Co Doped

The performance of radiation detectors used in positron-emission tomography (PET) is determined by the intrinsic properties of the scintillators, the geometry and surface treatment of the scintillator crystals and the electrical and optical characteristics of the photosensors. Experimental studies were performed to assess the timing resolution and energy resolution of detectors constructed with samples of different scintillator materials (LaBr3, CeBr3, LFS, LSO, LYSO: Ce, Ca and GAGG) that were fabricated into different shapes with various surface treatments. The saturation correction of SiPMs was applied for tested detectors based on a Tracepro simulation. Overall, we tested 28 pairs of different forms of scintillators to determine the one with the best CTR and light output. Two common high-performance silicon photomultipliers (SiPMs) provided by SensL (J-series, 6 mm) or AdvanSiD (NUV, 6 mm) were used for photodetectors. The PET detector constructed with 6 mm CeBr3 cubes achieved the best CTR with a FWHM of 74 ps. The 4 mm co-doped LYSO: Ce, Ca pyramid crystals achieved 88.1 ps FWHM CTR. The 2 mm, 4 mm and 6 mm 0.2% Ce, 0.1% Ca co-doped LYSO cubes achieved 95.6 ps, 106 ps and 129 ps FWHM CTR, respectively. The scintillator crystals with unpolished surfaces had better timing than those with polished surfaces. The timing resolution was also improved by using certain geometric factors, such as a pyramid shape, to improve light transportation in the scintillator crystals.

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Spreading of SARS-CoV-2 via Heating, Ventilation, and Air Conditioning Systems—An Overview of Energy Perspective and Potential Solutions

Journal of Energy Resources Technology ◽

10.1115/1.4048943 ◽

2020 ◽

Vol 143 (8) ◽

Author(s):

Ahmad K. Sleiti ◽

Samer F. Ahmed ◽

Saud A. Ghani

Keyword(s):

Air Conditioning ◽

High Performance ◽

Public Perception ◽

High Efficiency ◽

Uv Light ◽

Experimental Studies ◽

High Energy ◽

Penalty Cost ◽

Energy Penalty ◽

Air Conditioning Systems

Abstract The role of heating, ventilation, and air conditioning systems (HVAC) in spreading SARS-CoV-2 is a complex topic and has not been studied thoroughly. There are some existing strategies and technologies for health and high performance buildings; however, applications to other types of buildings come at large energy penalty: cost; design, regulations and standards changes, and varied public perception. In the present work, different factors and strategies are reviewed and discussed and suggested mitigations and solutions are provided including the required air flowrates with the presence of infectors with and without mask and disinfection techniques including ultraviolet (UV) light. Experimental and numerical research in open literature suggests that the airborne transmission of SARS-CoV-2 is sufficiently likely. However, in situ detailed experimental studies are still needed to understand the different scenarios of the virus spread. Displacement ventilation, underfloor air distribution, chilled beams, radiant ceiling panels, and laminar flow systems have varied effectiveness. High-efficiency particulate arrestance (HEPA) filters and UV light can clean viruses but at high energy cost. Suggested solutions to reduce the infection probability include recommended levels of ventilation and a combination of virus sampling technologies including cyclones, liquid impinger, filters, electrostatic precipitators, and water-based condensation.

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Flexural Toughness of High-Performance Concrete with Basalt and Polypropylene Short Fibres

Advances in Civil Engineering ◽

10.1155/2018/5024353 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 9

Author(s):

Piotr Smarzewski

Keyword(s):

High Performance ◽

High Performance Concrete ◽

Experimental Studies ◽

Polypropylene Fibre ◽

Experimental Results ◽

Fibre Content ◽

Flexural Toughness ◽

Hybrid Fibre ◽

Short Fibres ◽

Flexural Tests

In this work, an investigation is made to evaluate the flexural toughness of hybrid fibre-reinforced high-performance concrete (HPC) containing different combinations of basalt (B) and polypropylene (P) fibres. The experimental studies consisted of the three-point flexural tests on notched beam specimens. The specimens incorporated basalt/polypropylene (BP) fibres in 11 mixtures with proportions of 0/0, 100/0, 75/25, 50/50, 25/75, and 0/100% by volume at total volume fractions of 1 and 2%. The evaluation of the experimental results was done according to the CECS 13:2009 and PCS (postcrack strength) methods. The results indicate that high-performance concrete containing basalt/polypropylene fibre mixtures of 50/50% and with only polypropylene fibre content of 0/100% can be pronounced as the most appropriate combinations to be used in high-performance concrete for flexural toughness.

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Study on Electroplated Diamond Wire Saw Development and Wire Saw Wear Analysis

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.416.311 ◽

2009 ◽

Vol 416 ◽

pp. 311-315 ◽

Cited By ~ 2

Author(s):

Pei Qi Ge ◽

Yu Fei Gao ◽

Shao Jie Li ◽

Zhi Jian Hou

Keyword(s):

Current Density ◽

High Performance ◽

Experimental Studies ◽

Cathode Current Density ◽

Diamond Wire ◽

Wire Saw ◽

Diamond Wire Saw ◽

Cathode Current ◽

The Wire ◽

Electroplating Process

Development of high performance diamond impregnated wire is the key of application for fixed-abrasive wire sawing technology. In this paper, some experimental studies were done for development of electroplated diamond wire saw by employing the bright nickel bath. The wire saw electroplating process was developed, the effects of cathode current density and time at tack-on stage on diamond grits density and adhesion between saw matrix and plating coating were discussed. The wire saw cutting experiments were carried out for analysis the used wire wear using the scanning electron microscope (SEM). The experimental results show the optimum tack-on current density to obtain the wire saw with good abrasive distribution and adhesion is 1.5~2.0A/dm2, and the time of pre-plating, tack-on and buildup is 6, 8~10 and 18min in turn. Diamond wire saw wear includes coating wear and grain-abrasion, and the primary wear form is grits pulled-out.

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